Co-ordination compounds present in following biological systems:
A. Chlorophyll
B. Haemoglobin
C. Vitamin B12
D. Enzymes
E. Roots
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A, B, C and D only
Many molecules of living systems are coordination compounds, in which a metal ion is bound to ligand atoms (usually N or O) of an organic molecule.
(A) Chlorophyll — Correct. The pigment of photosynthesis is a coordination compound of magnesium.
(B) Haemoglobin — Correct. The oxygen carrier of blood is a coordination compound of iron.
(C) Vitamin B12 — Correct. Cyanocobalamine, the anti-pernicious anaemia factor, is a coordination compound of cobalt.
(D) Enzymes — Correct. Many enzymes, the biological catalysts, are metal complexes, e.g. carboxypeptidase A and carbonic anhydrase (zinc).
(E) Roots — Incorrect. Roots are a plant organ, not a compound. No metal ion bound to ligands is meant here, so roots are not a coordination compound.
NCERT (2026-27 edition):
Importance and Applications of Coordination Compounds – “… Coordination compounds are of great importance in biological systems. The pigment responsible for photosynthesis, chlorophyll, is a coordination compound of magnesium. Haemoglobin, the red pigment of blood which acts as oxygen carrier is a coordination compound of iron. Vitamin B12, cyanocobalamine, the anti–pernicious anaemia factor, is a coordination compound of cobalt. Among the other compounds of biological importance with coordinated metal ions are the enzymes like, carboxypeptidase A and carbonic anhydrase (catalysts of biological systems).”